Test & measurement

including a radiation oncologist to prescribe the appropriate treatment volume and dosage, a medical physicist and dosimetrist to determine how to deliver the prescribed dose and calculate the amount of time it will take the accelerator to deliver that dose, and a radiation therapist and machine expert to operate an accelerator to give patients the required radiation treatment. Professor Welsch comments that the gas jet

profiler would be “highly desirable for non-invasive beam profiling for medical LINACs. It would give access to continuous machine operation and reduce the time required for accelerator set-up and calibration. We could monitor the treatment beam without affecting it”.

enabling industry to benefit from accelerator science

In the past, Professor Welsch has found it frustrating that technologies being developed as part of funded projects have not been effectively commercialised. “As part of funded projects, we have developed

a range of beam diagnostic devices mostly as prototypes. We have developed them, built them, tested them and shown that they are working. “But as a university group, we need to keep

Gas jet beam profile monitor at the Cockcroft Institute. Credit: Cockcroft Institute

same time, the environment found in a particle accelerator usually generates high levels of electromagnetic interference, which further complicates precise measurements. The supersonic gas jet based beam profile

monitor offers a range of interesting possibilities. As the interaction uses excitation or ionization, which are well understood and usable with most projectile types, it offers intrinsic flexibility. Monitoring parameters such as acquisition rate and beam perturbation can easily be scaled by varying the gas species or target density and thus tailored for a particular application. Therefore, a gas jet based beam profile monitor can be used in most accelerators and light sources.

Wider applications for advanced technologies

Professor Carsten Welsch, head of the Department of Physics at the University of Liverpool and a senior academic at the Cockcroft Institute, believes that technologies being developed as part of the HL-LHC, such as the supersonic gas jet based beam profile monitor, have excellent potential to translate into medical and industrial applications. For example, linear accelerators (LINACs) are

widely used for radiation therapy. They generate x- rays or electron beams to conform to a tumour’s shape and destroy cancer cells while sparing normal tissue. Protons and heavy ions are also used in a very similar way for cancer treatment. Proton therapy currently requires a team

Instrumentation Monthly November 2020

moving onto the next big challenge, and not refine a particular technology for a specific instrument, as to do so would limited the opportunity for publications and therefore wouldn’t be very good for the careers of our PhD students and post-docs. “That was kind of a problem, because we put a

lot of effort to prove something was working, and just when it was working, we had to let it go.”

developing an innovation ecosystem

As a result of this experience Professor Welsch has been instrumental in establishing a series of pan-European research and training networks that see industry partners working closely with research establishments within an innovation ecosystem. The research fellows gain experience of cutting-edge research while building commercial skills in areas such as project management and developing contacts within an international community of accelerator scientists and engineers. One such network is AVA, ‘Accelerators

Validating Antimatter physics’, which also works with rare particles. He continues: “All of the industry partners that

are involved in the AVA project develop sensor technologies or detectors which at the moment are not broadly in use. “They are looking into proving what the

ultimate limit of detection precision and dynamic range is for these detectors. Within AVA they focus on antimatter beams initially, but clearly their detectors could be used for many other purposes. “Amongst low intensity beams, antiproton

beams are particularly challenging as they involve very small particles covering an enormous range of energies: every single particle needs to be detected. “New techniques are being developed within

AVA to monitor them. A good example is the use of diamond films. When the film is hit by a particle

it creates a little charge inside the diamond, which is then read out at a high frequency. “Developing sensor technology for particle

beams has attracted a lot of interest from industry partners. Demonstrating that their sensors can detect particles as elusive and exotic as antiprotons serves as a proof of concept that their technology is at the forefront of the field and can find its way into other applications – for example in medical imaging. “At the moment medical imaging doesn’t

have sensors that can detect every single particle, so increasing the resolution through improved particle capture would significantly help with the diagnostic process. “The creation of international technology

networks has proven to be a successful way to transition discovery science into industry. The fellows have proven highly employable and often transfer to the industry partners to further develop the technology.”

commercialising discovery science

Professor Welsch’s other approach to technology transfer has been through the creation of D-Beam, a spinout company from the Cockcroft Institute, which became one of the first companies to join the STFC CERN Business Incubation Centre. The QUASAR Group develops and optimises

particle accelerators, light sources and related technologies, with a focus on novel beam diagnostics. Present research is directed at frontier accelerators, such as the LHC and its upgrade; the design of novel accelerators including laser-driven and beam-driven plasma wakefield accelerators; and accelerator applications, medical applications and beam instrumentation. Professor Welsch explains: “The concept

behind D-Beam was to provide a commercial arm both for our own beam diagnostic developments, but also the ones being developed at CERN. My feeling is that with the contact network that we have developed around the world, and the involvement in medical projects and accelerator science in many different areas, that we have a very good position for offering a step-change in precision for the hundreds of large accelerators and synchrotron light sources that are currently in operation worldwide.” The HL-LHC-UK2 project was announced

on 11 September 2020 by the Science and Technology Facilities Council (STFC) and is a collaboration between CERN, the Cockcroft Institute, the John Adams Institute, STFC and eight universities. Companies interested in exploring further the

potential of accelerator science are welcome to contact Professor Welsch. More information is available at quasars/carsten_welsch/.

University of Liverpool

Cockcroft Institute of Accelerator Science and Technology


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